Cooling apparatus

ABSTRACT

According to one embodiment of the present invention, there is provided cooling apparatus. The cooling apparatus comprises an outlet for supplying chilled liquid, an inlet for receiving return chilled liquid, a free cooling system for providing first cooling to the return chilled liquid, a chiller unit for further cooling the first cooled return liquid to a predetermined temperature, a pressure difference sensor for measuring the pressure difference between the chilled liquid supplied at the outlet and the return liquid received at the inlet, and a flow control module for maintaining a predetermined pressure difference between the liquid supplied at the outlet and the return liquid received at the inlet.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of co-pending U.S. patent applicationSer. No. 13/382,105, filed Jan. 3, 2012, co-pending PCT applicationPCT/EP2010/058130, filed Jun. 10, 2010, and GB 0911868.8, filed Jul. 9,2009 (now abandoned), the entire contents of which are herebyincorporated by reference as though fully set forth herein.

BACKGROUND

For various economic and business reasons enterprises are increasinglycentralizing their backend computer systems in purpose built datacenters. Data centers typically house high concentrations and densitiesof such computer systems and additionally provide facilities such asuninterruptible power supplies and cooling systems necessary for theoperation of the computer systems in the data center.

Different data centers are typically unique in their requirements andcapacity, since the requirements of data centre customers are highlyindividual. Accordingly, the cooling requirements of data centers arealso highly individual and must be carefully designed to provide anappropriate amount of cooling for their associated data center.

However, designing and building custom cooling facilities is a complex,time-consuming and expensive task. Furthermore, as data centerrequirements change over time, for example through the addition of extracomputing capacity, corresponding changes may be required to the coolingfacilities.

SUMMARY

According to one embodiment, there is provided cooling apparatuscomprising an outlet for supplying chilled liquid, an inlet forreceiving return chilled liquid, a free cooling system for providingfirst cooling the return chilled liquid, a chiller unit for furthercooling the first cooled return liquid to a predetermined temperature, apressure difference sensor for measuring the pressure difference betweenthe chilled liquid supplied at the outlet and the return liquid receivedat the inlet, and a flow control module for maintaining a predeterminedpressure difference between the liquid supplied at the outlet and thereturn liquid received at the inlet.

BRIEF DESCRIPTION

Embodiments of the invention will now be described, by way ofnon-limiting example only, with reference to the accompanying drawings,in which:

FIG. 1 is a block diagram showing an overview of a data center accordingto one embodiment of the present invention;

FIG. 2 is a block diagram showing a simplified overview of a coolingmodule according an embodiment of the present invention; and

FIG. 3 is a block diagram of a modular cooling system according to anembodiment of the present invention.

DETAILED DESCRIPTION

Referring now to FIG. 1, there is shown an overview of a facility 100according to an embodiment of the present invention.

The facility 100 comprises a number of data center modules 110. In oneembodiment each data center module is a containerized data center modulehoused, for example, in any suitable transportable container such as anIntermodal Transport Unit (ITU), shipping container, POD (portable ondemand), or the like. In a further embodiment one or more of the datacenter modules may be a ‘bricks and mortar’ data center.

Each of the data center modules 110 house internal cooling equipment,such as computer room air handling (CRAH) units, and air handling units(AHU), that require a supply of chilled liquid, such as chilled water,in order to operate.

To supply chilled water to the data center modules 110, one or morecooling modules 102 are provided. The cooling modules 102 may, forexample, be housed in a transportable container, such as an ITU, a POD,a shipping container, or the like.

Each cooling module 102 has a chilled water supply outlet 116 and awarmed chilled water return inlet 118 which are connected todistribution pipework 112 and 114 respectively. Each data center module102 is removably connected to the distribution pipework 112 and 114through isolation valves 104 and 106. Cooling equipment, such as CRAHsand AHUs, within each data center module 110 is also removably connectedto the distribution pipework 112 and 114.

In this way, chilled water provided from the outlets 116 of the coolingmodules 102 is provided to cool the internal cooling equipment of eachdata center module 110. Warmed return chilled water is returned to thecooling modules 102 through return inlets 118.

Each cooling module 102 provides up to a predetermined cooling capacityand is factory tested and configured to supply chilled water against apredetermined external differential pressure. The pressure differencebetween the inlets and outlets of each cooling module may be setindividually to ensure that all cooling loads in the data centre may bemet. In this way, each cooling module 102 provides a variable flow ofchilled water to the distribution pipework 112. The cooling modules 102are described in further detail below.

In one embodiment, the cooling modules 102 are configured to supply avariable flow of chilled water at a substantially constant supplytemperature. In a further embodiment, the cooling modules 102 areconfigured to supply a variable flow of chilled water at a substantiallyconstant return temperature.

Advantageously, by providing modular cooling modules 102 the design andimplementation of a data center cooling system can be substantiallysimplified. For example, when the data center 100 is designed, thecooling requirements of the initial design can be determined and one ormore cooling modules 102 can be included in the data center to providean appropriate amount of cooling. This avoids the need to design fromscratch a ‘bricks and mortar’ type custom built chilled water system.Additionally, since the cooling modules 102 provide a variable flow ofchilled water, the cooling modules 102 provide only the amount ofchilled water required by the cooling systems of the data centermodules.

Furthermore, if the cooling requirements of the data center changeovertime, for example, through the addition or removal of computingequipment, cooling modules may be added or removed from the data centerin a simple manner. Additionally, since each cooling module is factorytested, installation of such a module is greatly simplified, requiringlittle more than connection to the distribution pipework 112 and 114, anappropriate power supply, and a water supply. If applicable, connectionmay also be made to an evaporative cooling plant, such as adiabaticcoolers and cooling towers. Yet further, the cooling modules 102 areconfigured to use free cooling when ambient conditions allow therebyincreasing their energy efficiency.

FIG. 2 shows a simplified block diagram of a cooling module 200according to an embodiment of the present invention. In the accompanyingdrawings solid connecting lines are used to represent pipework anddashed connecting lines are used to represent control signals.

The cooling module 200 has an outlet 202 which supplies chilled waterand an inlet 204 which receives warmed return chilled water. The warmedreturn chilled water is chilled water that has been warmed, for example,during the creation of cooled air, such as by mechanical airconditioning units. The warmed return chilled water is fed through achiller unit 210 that cools the warmed return chilled water to a desiredtemperature.

The chiller unit 210 comprises a free cooling module 212 for cooling thereturn water through non-mechanical chilling means such as heatexchangers. The chiller unit 210 also includes a mechanical chiller 211,such as a refrigeration loop, for further chilling the cooled returnwater when free cooler module 212 is unable to cool the return water tothe desired temperature. In one embodiment, the mechanical chiller unit211 is configured to cool the warmed return chilled water by 5 to 10degrees, although those skilled in the art will appreciate that in otherembodiments a greater or lesser degree of cooling may be obtained tomeet specific requirements.

In alternative embodiments, the non-mechanical and mechanical chillingmeans are used in parallel, so that the system can operate either withmechanical cooling, free cooling, or both mechanical and free cooling.

The cooling module 200 additionally includes a pressure sensor 206 formeasuring the outlet water pressure at, or in close proximity to, theoutlet 202. A further pressure sensor 208 is provided for measuring thereturn water pressure at, or in close proximity to, the return inlet204. A control logic module 214 obtains the two pressure measurementsand determines the pressure differential between the inlet and outletpressures. The control logic 214 controls a flow control module 216 tomaintain a predetermined pressure differential between the inlet 202 andoutlet 204. Additionally, a pressurization module (not shown) may usedto maintain a liquid pressure above atmospheric pressure, to preventcavitation within the flow control module 216. The flow control modulemay comprise, for example, one or more variable speed pumps.

One advantage this arrangement brings about is that all the controlloops and cabling are contained within the chilled water supply module,thereby avoiding having connections and wiring further down the chilledwater distribution system. This increases the modularity of the coolingmodule 200.

Referring now to FIG. 3, there is shown a more detailed view of amodular cooling module 300 according to one embodiment of the presentinvention.

The cooling module 300 has a chilled water outlet 116 through whichchilled water is output, and a return inlet 118 through which warmedchilled water is returned to the cooling module. The outlet 116 andinlet 118 are connected respectively to isolating valves 304 and 302.These valves enable the cooling module 300 to be isolated andtransported with ease, and enable quick and easy connection within afacility 100 such as a data center.

Warmed return chilled water is received at inlet 118 from, for example,a data center module 110. The warmed return chilled water passes througha heat exchanger 306, such as a plate heat exchanger. The heat exchanger306 is arranged to cool the warmed return chilled water through freecooling. The cooled chilled water is then pumped, by pump 308, through achiller unit 309. The pump 308 is used to ensure a predetermineddifferential pressure, as previously described. The chiller unit 309 iscomprised of an evaporator 310, a condenser 316, a compressor 312, anexpansion device 314, and control logic 317. The control logic isconfigured so the chiller unit 309 outputs water at a substantiallyconstant predetermined or programmed temperature.

Depending on the temperature of the water cooled by the heat exchanger,the chiller unit 9 may or may not need to function, or may need tofunction partially at a reduced part load. For the purposes of thisexample, assume that the cooling module 300 is configured to supplychilled water at 15 degrees Celsius. If warmed return chilled water isinput to the heat exchanger at 20 degrees Celsius, and is cooled by theheat exchanger, through free cooling, to 15 degrees Celsius no furthermechanical cooling of the water is required. In this case, the chillerunit control logic 317 may stop or reduce the functioning of the chillerunit.

If, however, the heat exchanger is only able to cool the water to, say,17 degrees Celsius, for example if the return water is at a highertemperature or if ambient conditions do not allow for sufficient freecooling of the return water, the chiller unit control logic 317 controlsthe operation of the chiller unit 309 to provide the water output fromthe chiller unit 309 at the predetermined temperature. Such control maybe achieved, for example, in any suitable manner, such as by controllingthe compressor 312 speed, inlet guide vanes, control valves, cycle time,etc.

The condenser water warmed by the heat exchanger 306 is cooled using,for example, a dry/adiabatic cooler or cooling tower 318.

A condenser water bypass 319 is provided to allow water from the outputof the condenser 316 to be fed back to the input of the condenser 316 orto bypass it to avoid problems with the condenser temperature becomingtoo low. The opening and closing of the condenser water bypass 319 iscontrolled by an automatic valve 321, controlled by the chiller controllogic 317.

To ensure that the chilled water supplied at outlet 116 is supplied at aconstant differential pressure, pressure gauges 326 and 324 areprovided. Pressure gauge 324 measures the pressure of the return chilledwater at, or in close proximity to, inlet 118, and pressure gauge 326measures the pressure of the chilled water at, or in close proximity to,outlet 116. Based on the measured inlet and outlet pressures thecontroller 322 ensures that an adequate pressure difference ismaintained between the returned water and the chilled water output bycontrolling the speed of the pump 308, through a variable frequencydrive module 320. By ensuring an adequate pressure difference ensuresthat the chilled water supplied by the cooling module 300 is able tocirculate in distribution pipework 112 and 114 of a data center 100,whilst ensuring correct operation of any other cooling modules presentin the data center. Typical differential pressures may be in the rangefrom approximately 100 kPa to 500 kPa, although this may be varieddepending on specific circumstances. The pressure differential iscontrolled to avoid problems of pump cavitation at low pressures and tokeep the pressures below maximum design pressures of the facility.

An evaporator bypass 311 is provided to allow the chiller unit 309 tooperate below its minimum flow rate, for example with low cooling loads.The chiller unit 309 will normally have its own differential pressurecontroller across the evaporator to ensure its minimum flow rate issatisfied. Below this minimum flow rate it will disable the chiller. Thebypass 311 bypasses chilled water from the chiller unit 309 back to theinput of the chiller unit 309. The evaporator bypass 311 is controlledthrough an automatic valve 313 controlled by controller 317.

When assembling the cooling module 300 factory testing is performed toensure that the cooling module 300 is able to provide the requiredamount of cooling and that all its control functions operate correctly.Testing is achieved using a load bank 328 that is detachably connectedto the outlet 116 and inlet 118. When the load bank 328 is present, thevalves 304 and 302 are shut and the valves 330 and 232 are opened.

The load bank 328 may be any suitable heat source, such as a boiler,used for generating a predetermined amount of heat for heating upchilled water output from the cooling module 300. The load bank 328 mayalso reduce the pressure of the supplied chilled water, to simulate thepressure reduction experienced in a typical data center 100. In thisway, the cooling module 300 can be fully configured and tested to ensurecorrect operation over a wide range of conditions.

Once the correct operation of the cooling module 300 has been verified,the load bank 328 may be removed from the cooling module 300, and thecooling module 300 is then ready to be installed and used in a datacenter, such as data center 100.

In a further embodiment, the cooling module 300 is configured to providereturn water at a substantially constant temperature. This may beachieved, for example, by monitoring to the temperature of the returnwater and by adjusting the output temperature of the chiller unit 309 inaccordance therewith, such that the return water is at a substantiallyconstant temperature. One advantage of maintaining a substantiallyconstant return water temperature is that the chilled water temperaturemay be raised, depending on the current cooling load, leading topotentially large energy savings.

Those skilled in the art will appreciate that reference made herein towater and water cooling systems is not limited thereto, and that anyother suitable liquids, such as brines (i.e. glycol/water), refrigerants(i.e. carbon dioxide, etc), may alternatively be used.

Those skilled in the art will also appreciate that reference herein todata centers may include any other types of facilities having coolingrequirements, such as power plants, mechanical installations, and thelike.

Cooling apparatus, comprising: an outlet for supplying chilled liquid;an inlet for receiving return chilled liquid; a free cooling system forproviding first cooling to the return chilled liquid; a chiller unit forfurther cooling the first cooled return liquid to a predeterminedtemperature; a pressure difference sensor for measuring the pressuredifference between the chilled liquid supplied at the outlet and thereturn liquid received at the inlet; and a flow control module formaintaining a predetermined pressure difference between the liquidsupplied at the outlet and the return liquid received at the inlet. Thepressure difference sensor may comprise a pressure sensor in proximityto the inlet, and a pressure sensor in proximity to the outlet. Acontrol logic for determining the differential pressure of the liquidbetween the inlet and outlet, the control logic configured to controlthe flow control module to maintain a substantially constantpredetermined differential pressure. The flow control module maycomprise a variable speed pump. The apparatus may be configured suchthat the chiller unit is only operated when it is determined that thetemperature of the first cooled return liquid is above a predeterminedtemperature. The apparatus may be configured to supply a variable amountof chilled liquid at a constant supply temperature. The apparatus may beconfigured to supply a variable amount of chilled liquid at a constantreturn temperature. The chilled liquid is any one of water, a brine, anda refrigerant. Further, a facility comprising: one or more data centermodules, each data center module having one or more cooling elementsrequiring a supply of chilled liquid through a distribution pipework;the cooling apparatus as one or more cooling modules removably connectedto the distribution pipework.

1-10. (canceled)
 11. A cooling apparatus to process a chilled liquid,comprising: an outlet to provide a chilled liquid supply; an inlet toreceive a chilled liquid return; a heat exchanger to cool the chilledliquid return by free cooling; a mechanical chiller comprising arefrigeration loop to further cool the chilled liquid return to apredetermined temperature, wherein the heat exchanger and the mechanicalchiller to utilize a circuit of free cooling fluid as a cooling medium;and a flow control module to facilitate maintaining a predeterminedpressure difference between the chilled liquid supply and the chilledliquid return.
 12. The cooling apparatus of claim 11, comprising: afirst pressure sensor to measure pressure of the chilled water supply;and a second pressure sensor to measure pressure of the chilled waterreturn, wherein a control logic to determine the differential pressurebetween the chilled water supply and the chilled water return, and thecontrol logic to control the flow control module to maintain thepredetermined pressure difference.
 13. The cooling apparatus of claim11, wherein the flow control module comprises a variable speed pump. 14.The cooling apparatus of claim 13, wherein a control logic to controlthe flow control module to maintain the predetermined pressuredifference by controlling speed of the variable speed pump via avariable frequency drive.
 15. The cooling apparatus of claim 11, whereinthe flow control module to facilitate maintaining the predeterminedpressure difference to avoid pump cavitation and to maintain pressurebelow design pressure.
 16. The cooling apparatus of claim 11, whereinthe flow control module comprises a pump, wherein the free cooling fluidcomprises cooling tower water, and wherein the heat exchanger to be acomponent of a free cooling system comprising a cooling tower and tocool the chilled liquid return by non-mechanical chilling via thecooling tower water.
 17. The cooling apparatus of claim 11, wherein themechanical chiller comprising the refrigeration loop comprises anevaporator, a condenser, a compressor, and an expansion device, andwherein the condenser utilizes the free cooling fluid as the coolingmedium.
 18. The cooling apparatus of claim 11, comprising a controllogic to control operation of the mechanical chiller to provide thechilled liquid supply at the predetermined temperature, and wherein tocontrol operation of the mechanical chiller comprises to control speedof the compressor.
 19. A cooling apparatus to process a chilled liquid,comprising: a container housing; an outlet to provide a chilled liquidsupply; an inlet to receive a chilled liquid return; a heat exchanger tocool the chilled liquid return; a chiller to further cool the chilledliquid return to a predetermined temperature, wherein the heat exchangerand the chiller to utilize cooling tower water as a cooling medium; anda flow control module to maintain a predetermined pressure differencebetween the chilled liquid supply and the chilled liquid return
 20. Thecooling apparatus of claim 19, wherein the container housing comprises atransportable container, wherein the cooling module to supply chilledliquid in a data center, and wherein the flow control module comprises apump.
 21. The cooling apparatus of claim 20, comprising a pressurizationmodule to facilitate maintaining the chilled liquid above atmosphericpressure to substantially prevent cavitation within the pump, andwherein the chiller to further cool the chilled liquid return comprisesthe chiller to further cool the chilled liquid return in response to atemperature of the chilled liquid return discharging from the heatexchanger being above a predetermined temperature.
 22. The coolingapparatus of claim 19, wherein the cooling apparatus to supply chilledliquid to internal cooling equipment of a containerized data centermodule, wherein the chiller comprises a mechanical chiller including arefrigeration loop having a condenser, and wherein the cooling towerwater as a cooling medium for the chiller to be utilized by thecondenser.
 23. The cooling apparatus of claim 19, wherein the heatexchanger comprises a plate heat exchanger.
 24. The cooling apparatus ofclaim 19, wherein the cooling apparatus to supply a variable amount ofchilled liquid at a substantially constant supply temperature.
 25. Thecooling apparatus of claim 19, wherein the cooling apparatus to supply avariable amount of chilled liquid at a substantially constant returntemperature.
 26. A method of processing a chilled liquid for a datacenter via a cooling module, comprising: supplying a chilled liquidsupply to the data center via an outlet of the cooling module, thecooling module comprising a heat exchanger and a chiller; receiving achilled liquid return from the data center via an inlet of the coolingmodule; cooling the chilled liquid return via the heat exchanger;cooling further the chilled liquid return to a predetermined temperaturevia the chiller, the chiller comprising a condenser; flowing a stream ofa free cooling medium through the heat exchanger and the condenser; andpumping the chilled liquid to circulate the chilled liquid throughcooling equipment of the data center and to maintain a predeterminedpressure difference between the chilled liquid supply and the chilledliquid return.
 27. The method of claim 26, comprising: measuring supplypressure of the chilled liquid supply and measuring return pressure ofthe chilled liquid return; and determining via control logic a pressuredifferential between the chilled liquid supply and the chilled liquidreturn, wherein maintaining the predetermined pressure differencecomprises the control logic controlling a flow control module, the flowcontrol modules comprising a pump, and wherein pumping the chilledliquid comprises pumping the chilled liquid via the pump.
 28. The methodof claim 27, wherein the cooling module comprises a container housingand the pump, wherein the cooling equipment comprises internal coolingequipment of data center modules in the data center, and whereinsupplying the chilled liquid supply comprises supplying the chilledliquid supply to the internal cooling equipment of the data centermodules.
 29. The method of claim 26, wherein the free cooling mediumcomprises cooling tower water, and wherein the chiller employs arefrigeration loop.
 30. The method of claim 26, wherein the free coolingmedium comprises cooling tower water, wherein flowing the stream of thecooling tower water comprises supplying from a cooling tower the streamto the heat exchanger and condenser, and returning the stream to thecooling tower, and wherein the chiller comprises a compressor, anevaporator, and an expansion valve.